/Engine/Source/Editor/ContentBrowserData/Public/ContentBrowserDataSource.h
Called to provide custom drag and drop handling when a drag event leaves an item, such as clearing any error information set during earlier validation.
True if this data source can handle the drag event (even if it won't because it's invalid), or false to allow another data source (or the default handler) to deal with it instead.
virtual bool HandleDragLeaveItem ( const [FContentBrowserItemData](API\Editor\ContentBrowserData\FContentBrowserItemData) & InItem, const [FDragDropEvent](API\Runtime\SlateCore\Input\FDragDropEvent) & InDragDropEvent )